Effects of hydrophilic and hydrophobic SiO2 composite organic resin coating on properties of FeSiCr magnetic powder cores

The effects of hydrophilic and hydrophobic SiO2 composite organic resin on the properties of FeSiCr magnetic powder cores and the effects of annealing treatment on magnetic properties were studied. After phosphating, the FeSiCr alloy powders were coated by two types of SiO2 composite resin, which are hydrophobic and hydrophilic, respectively. The FeSiCr magnetic powder cores were prepared by compaction and curing. The results show that the coating effect of coupling modified hydrophilic SiO2 composite organic resin is better than that of hydrophobic SiO2 composite organic resin. With the increase of SiO2 addition, the specific resistance and coercivity of the magnetic powder cores are increased, while the density, saturation magnetization and effective permeability are decreased. The FeSiCr magnetic powder cores coated with 0.5% hydrophobic SiO2 composite organic resin have excellent comprehensive performance after annealing. Under the condition of 20 mT, 100 kHz, the magnetic core loss is 49.84 kW/m3, which is 16.9% lower than that of the magnetic powder cores coated with pure resin. Annealing can effectively promote magnetic properties of FeSiCr magnetic powder cores.